FIELD OF THE INVENTION
This invention relates to the so-called "electro spray ionization" of molecules (frequently abbreviated to ES or ESI). This method is, in general, carried out by spraying aqueous solutions from a spray capillary under the influence of an electric field. The method is especially suited for the ionization of large molecules, especially bio molecules, and for their analysis by mass spectrometry after introduction into the vacuum system of the spectrometer.